Manuel wither



' NJPETERS, FHOTD-LITHOGRAPHER. WASHINGYON, D. C.

UNITED STATES I PATENT OEETCE.

MANUEL VI'IMER, OF SOUTH PEKIN, NEW YORK.

MACHINE FOR GRINDING AND POLISHING LENSES.

Specification forming part of Letters Patent No. 40,303, dated October13, lt-SGB.

To all whom it may concern:

Be it known that I, MANUEL WITMER, of South Pekin, in the county ofNiagara and State of New York, have invented certain new and usefulImprovements in Apparatus for Grinding and Polishing Lenses; and I dohereby declare that the following is a full and exact descriptionthereof, reference being had to the accompanying drawings, making partof this specification.

Figure l is a perspective view of my improved machine; Fig. 2, a sideelevation thereof, a portion being shown in section; Fig. 3, a plan ofthe gearing and crank-plate detached; Fig. 4, a plan of the basindetached.

Like letters of reference indicate corresponding parts in all thefigures.

It is my object to produce a machine by which lenses may be ground andpolished automatically, and withoutthe manipulation necessary in theusual process.

A suitable frame, A, is provided, in one end of which is mounted avertical shaft, a, having secured to its upper end a disk or equivalentsupport, B. This shaft receives motion preferably by means of aspur-wheel, C, secured to it, which wheel engages with a similar pinion,D, on a vertical driving-shaft, b, that is actuated by means of a bandrunning on a pinion, e, or in any desirable manner.

On top of the main frame is situated a sliding carriage, E, the forwardend of which forms a crank-connection with the drivingshaft b by meansof a wrist (shown in dotted lines, Fig. 2) and crank-plate G on the endof the latter shaft, said wrist connecting with holes e e of thecrank-plate. These holes are at varying distances from the center of theplate, so that by adjusting from one to the other a greater or lesslength of stroke may be obtained, as desired. The rear endof thecarriage rests in a guide, d, Fig. 2, which allows a free longitudinalmovement.

At a suitable position in the' rear the carriage is provided with across-piece, f, secured thereto by means of a bolt, g, passing through alongitudinal slot, h, in the carriage, and this cross-piece in turn hasuprights it' respectively at opposite ends, which form bearings for anaxis, k, to which is jointed a light frame, H, branched in the rear, butconverging in front and forming a circular opening, l, as clearlyrepresented in Fig. 1. A

standard, I, extends upward in the rear of this opening, and this has aright-angled arm, m, which sustains in any suitable manner a shaft, K,extending downward through the opening, and having rigidly secured to itat that point a friction-wheehv'n, fitting within the opening andresting against its side.

If desirable, the sides inclosing the opening and also thefriction-wheel may be cut with cogs, the one part gearing into theother, but the same effect is produced by the friction of the two smoothsurfaces, the design being to give the shaft a revolving motion as it isoperated, as will presently be described.

The lower end of the shaft K is made pointed, oftriangular or otherequivalent shape, and fits loosely in a correspondinglyshaped hole orsocket of a cover, P', which holds the lens q in place while it is beingground and polished.

The lens rests `upon a basin, L, which in turn is supported by the diskB, already described. This basin consists' of two parts, a

rim or band, r, of conical shape and considerable width, and an interiorbed, s, which fits closely within the rim. The bed may be eitherconcave, as represented in the drawings, convex, or plane, as may bedesirable, to grind the lens of proper shape. The bed properis grooved,as represented in Figs. 1 and 4, being divided into sections by radialgrooves tt,

and the respective intermediate sections filled by grooves t t',parallel with the leading radial groove. Thus, the intermediate parallelgrooves of one section are angular to those of the next section. The bedis also provided on the outer edge with a channel or depression, u,extending the whole distance around.

For producing the necessary pressure of the lens upon the bed ingrinding and polishing, a bow, M, is secured to the standard I, curvingbackward, and jointed at the opposite end to the axis k. A coiledspring, N, or equivalent, is attached at one end to the carriage E, andat the opposite end to the bow, in such a manner that it may be adjustedup and down to produce a greater or less degree of pressure. Thusarranged there are several motions produced in grinding the lens: First,the revolution of the basin itsclf'by means of the shaft on which itrests; second, the forward and backward reciprocation of the lensproduced by the carriage and frame H 5 third,

the lateral play produced by the crank-plate Gr, and, fourth, theindependent revolution of the lens, by means of the friction-Wheel n.lhis last action is produced by the frictionwheel engaging with thesides ofthe opening l during the reciprocations and the lateral movementofthe carriage. By this variety of motion a more equal friction on thesurface of the lens is produced, and consequently it is ground betterthan usual. In order that the lens shall not pass over the same path onthe bed at every revolution, and consequently Wear the surface ofthe bedunequally, I prefer to make the number of teeth on the spur- Wheel C andpinion l) about in the proportion of 4% to l, which is the ratio shownin the drawings. rlhis proportion, however, may be varied slightly, sothat the fraction may be either greater' or less than one-half, but theeven fraction is to be avoided. By this arrangement a new path ot' thelens is produced for a great number of revolutions, thus wearing thesurface of the bed equally and preserving the proper shape of the lensitself.

The arrangement ofthe grooves t t is such as to retain the emery best,especially where the bed is concave, for in its passage over the bed thelens has a tendency to work the einery outwai d in the angular groovest, thus opposing its gravitation, which would not be the case if theywere all radial, the action of the vmery in that condition being to runto the center. rIhe situation of the grooves is also such as to producethe best effect in grinding, as they present a better surface to thelens. Iy means of the rim r and channel 1l a sufficient amount ol" wateris retained in the basin at all times for keeping the emery wet, thussaving the necessity of applying water continually, as would otherwisebe the case. The conical shape of the rim allows the bed to be insertedwater-tight or removed at pleasure for cleaning. This is of consequence,for in polishing after the grinding is accomplished it is necessary toemploy the same basin in order to preserve the perfect form ofthe lens,and in polishing the emery must be a-ll removed and rotton stone used inits place. In polishing, also, a greater degree of pressure is duced bysimply turning the coiled spring' N up as indicated by red lines in Fig.2. 3y

this arrangement of the spring the pressure may be varied to any degreedesired, while the action of the carriage is not interfered with in theleast.

The frame H, together with the shaft K, can be turned back on the axisk, as indicated by red lines in Fig. 2, for inserting the lens on thebed or removing it. By adjusting the crank-connection of the carriagefrom one to another ot' the holes e e in the crank plate a greater orless length of stroke of the carriage is produced, and consequently alarger or'smaller lens may be ground. The slot It in the carriage allowsthe cross-piece f to adjust itself to any change in thecrank'connection.

By this arrangement I produce lenses in a greater degree free fromspherical aberation.

Vhat I claim as my invention, and desire to secure by Letters Patent,is-

l. Grinding and polishing the lens upon the basin'L when the basin has aturning motion and the lens has an independent revolving motion of itsown, and a vibrating, longitudinal, and lateral motion, produced by thereciprocation ofthe carriage in such a manner that said lens travels ina new path overthe surface of the basin at each revolution, sub-Vstanti-all y as herein set forth.

2. In combination with the outer channel, u, the rim r, arrangedsubstantially as and for the purpose herein specified.

3. The combination and arrangement ofthe In witness whereof I havehereunto signed' my name in the presence of two subscribing witnesses.

MANUEL WIIMER.

Witnesses:

BENDIcKr MAURER., SAMUEL frm/IER.

